1. Field of the Invention
The present invention relates to a paper machine fabric, especially a forming fabric.
2. Description of the Related Art
In the known multi-layer paper machine fabrics, two woven fabric layers are held together either with binding machine direction or cross machine direction yarns. While running in the paper machine, sections of a paper machine fabric are under severe longitudinal tension. The paper machine fabric therefore stretches in its longitudinal direction (machine direction) and contracts in its width (cross machine direction).
In paper machine fabrics whose woven fabric layers are connected with each other by cross machine direction binder yarns, there exists the problem that the connection between the woven fabric layers loosens due to the contraction of the fabric in a cross machine direction, causing the internal friction between the woven layers to intensify. A strong internal friction between the woven fabric layers leads to a premature wear of the paper machine fabric and, thereby, often to a shortened lifespan.
In paper machine fabrics whose woven fabric layers are connected with each other by machine direction binder yarns, there exists the problem that the binder yarns are heavily stretched due to the stretching of the fabric in the machine direction. This leads to a constriction at the crossover points of the binder yarns and, therefore, to a constriction and an unevenness in the paper-side woven fabric layer. If, in contrast, the machine direction binder yarns are woven so loosely that the problem described above cannot occur, then the sections of woven fabric layers in which the fabric is under a slight longitudinal tension are not connected firmly enough with each other, causing an internal friction of the forming fabric.
What is needed in the art is a paper machine fabric with improved strength and minimal internal friction in which the aforementioned disadvantages are prevented.